Combined thermostat and automatic pilot control



g- 1952 s. G. ESKIN EIAL 2,607,530

COMBINED THERMOSTAT AND AUTOMATIC PILOT CONTROL Filed June '17, 1950 3Sheets-Sheet 1 3 W F iw- TH ['18 ATTO/ZAZ'Y Aug. 19, 1952lllllllllllllllllIlllllllllllllllllllllll. v

8.6. ESKIN ETAL 2,607,530

COMBINED THERMOSTAT AND AUTOMATICPILOT CONTROL Filed June 17, 1950 3Sheets-Shet 2 Sac/22a 6'. 55612, Adele Ana algal: and Hapofl PK Rice.

g- 1952 5. 5. ESKIN El'AL COMBINED THERMOSTAT AND AUTOMATIC PILOTCONTRQL Filed June 17, 1950 3 Sheets-Sheet 5 nvmvraea' Samzue!61%.55512,

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Patented Aug. 19, 1952 UNITED STATES PATENT OFFICE COMBINED 'rHERMosTATAND AUTOMATIC I I PILOT CONTROL I Sam uel G. Eskimli'aroid W. Rice, andAdele M.

Arkelyan, Los Angeles, Calif., assignors to Rob- I ,ertshaivFultoii'Controls Company, Greensburg, Pa.,'a corporation of Delaware ApplicationJune r1, 1950, Serial No. 168,791

This invention relates to combination controls for gaseous fuel burnerswherein the temperature controlling device and the pilot cut-off bothoperate upon a single control valve.

The present inventioriis particularly adapted, although not limited, for.usewith gas burning water heaters and the like-wherein watertemperatures are controlled within precise limits. The thermostaticdevice which is responsive to the water temperature is preferably of therodandetube type having, temperature adjustment means located on thecontrol body for ready access by t he user. The automatic pilot controlin this embodiment includes an expansible thermal element of the mercuryvapor-pressure type responsive to the flame of the pilot burner.

Since provision may be made for complete shut-off of fuel to boththe-main and pilot burners under automatic control a separate pilotvalve can be'provided for conjoint operation to closed position withthe. main burner valve. Operation of such a pilot valve to open positioncan conveniently be effected by a control handle on the body adjacentthe temperature adjustment means. An interlock between the main gas cockand the pilot valve Will permit operation of the latter to open positiononly when the gas cock is in the Pilot position and is thus-positionedfor preventing now of fuel to the main burner valve. Thereafter, thepilot valve is maintained open by operation of the automatic pilotcontrol whenever the pilot burner is producing a flame for heatingthe'expansibl'e thermal element. I I I The inventionincludesa novellever system operative between the main burner valve and the thermostatand automatic pilot control and also between the pilot valve, whereprovided, and the control handle for correlating the action of theseparts to provide complete safety in starting and under normalrunhihgconditions, The levers are removed from the path of gas flow andare not subject to corrosive influences. Moreover, a fail-safe type ofu'nit is provided to prevent leakage of gas underabnormal conditions.

With theseandother objects and advantages in view a preferred embodimentof the invention is illustrated in the accompanying drawings wl erein:

Fig. 1 is a plan view of the control device,

Fig. 2 is a front elevation of the control device shown in Fig. 1, g sFig. 3 is a cross-section taken on the line IlI+IIIof Fig. 2 butrevolved ninety degrees,

Fig. 4 is a partial cross-section taken on the 7 Claims. (01. 236-21)line IV--IV of Fig. 1 but revolved ninety degrees, Fig. 5 is asec'tiontaken on the line V-'V of Fig.2,

Fig. 6 is a partial front elevation of the control sh ownin Fig. 1 butrevolved 90,

Fig. 7 is a section taken onthe line vn vn o'fFig.2,and I Fig. 8 is apartial cross section taken on the line VIII-VIII f Fig. 1. I

Main shut-0 7 cock Referring more praticularly to the drawings, thecontrol device comprises a casing It provided at one end with a lateralinlet opening I2 for fuel and at the other end with an outlet opening I4 for the fuel. A main fuel passage IE through the casing to providescommunication between the inlet l2 and the outletv M. As is customary insuch devices suitable pipe connection may be provided at the inlet I2and the outlet It to convey 'fu'elthrough the passage 16 tov a mainburner (not shown) of the appliance upon which the control is to beused.

The passage of fuel between the inlet 12 and the outlet 14 is undercontrol er a. main shut-off cock 1 8. The cock I8 is provided with anangular port whichismovableupo'iimanual rotation of the cock l8 by aknob 22 to open and close communication through the passage 16 betweenthe inlet I2 and the outlet l i Preferably, the knob 22 carries theus'ual indicia (not shown) for the ON OFF and "Pllot positions of themain shut-oil cock I8 which are adapted to register selectively with apointer 24 secured to the casing I0 inan appropriate location. I V

The knob 22 is also adapted for axial movement relative to the cockl8and--is provided on its under side with a-substantially annular recess25 which, however; is interrupted by an unrecessed or land portion '28,Fig. 5, which lies oppo site the indiciafi ilot. A plunger 36 projectsthrough the casing :9 substantially parallel with the axis ofthe mainshut-off cock l8 and is adapted to be engaged by the land portion 23upon axial movement of the knob 22' when in the Pilot position. Theplunger iifl is biased. by a coil spring 32 outwardly of the casing IE]but such movement is limited by engagement of a collar 34 formed on theplunger with the interior bottom Wall of a cap nut 36 on the casing l0and through Whichtheplunger 39 projects. Rotation of the cock [8 islimited to an arc of approximately" 180 betweenl the oer and ON,positions'by an adjustable stop element 38 which projects from the knob22 for engage- 3 ment with one side of the plunger 30 and by an abutment39 on the underside of the knob 22 for engagement with the opposite sideof the plunger 30.

Pilot value As shown more clearly in Figs. 3-5 the casing I is providedwith an integral hollow boss 40 disposed on one side of the shut-offcock I8 and provided with a filter cartridge 42 for the pilot fuel. Thebottom Wall of the filter cartridge 42 is suitably sealed, as at 44, influid-tight connection with the bottom wall of the hollow boss The outerwall of the cartridge 42 is, how-' ever, spaced from the inner wall ofthe boss 49 to provide for passage of fuel therebetween. To

this end, a passage 45 is formed in the casing Iil for communication atone end with an arcuate groove 48 in the side wall of the shut-ofi cockI8 forming an extension of the port 29 therea through. The groove48afiords communication between the port 29 and the passage 46 when theshut-off cock is in the ON position and fuel is passing directly fromthe port 20 to the main fuel passage I6. 7 p

The opposite end of the passage 46 communicates with the hollow boss 40adjacent the center of the filter cartridge 42 which thereby receivesfuel to be filtered and emitted at the opposite end thereof. A pilotpassage ,59communicates at one end with the space between the outer wallof the filter cartridge 42 and the inner wall of the hollow boss 49 andthereby forms an inlet passage to a pilot valve chamber 52 formed in thecasing. I0 to one side of the main fuel cock I8. A pilot valve member 54is mounted in the chamber 52 and is reciprocable on an axissubstantially parallel with that of the plunger 30 to open and close apassage through a valve seat member 56 which is supported in the chamber52. A closure cap 51 provides access to the valve member 54 and alsoforms a seat for one end of a coil spring 59 serving to bias the valvemember 54 toward its seat 55. An outlet passage 58 communicates with thepassage in the valve seat member56 and thus receives a supply of fuelfrom the inlet passage 50 when the valve member 54 is in open position.The opposite or outlet end of the passage 58 terminates in a suitableconnection SI for a pilot conduit for supplying fuel to a pilot burner(not shown). The usual adjusting-means 63 is provided in the passage 59for flow of fuel to the pilot burner.

Movement of the pilot valve member 54 between open and closed positionsis eifected by operation 'of a valve stem 69 which projects through-thepassage in the valve seat member 56 and is suitably fluted ornoncircular to permit passage of fuel thereby. The usual sealingdiaphragm 64 is provided for the operating end of the valve stem 60 toprevent leakage of fuel from the chamber 52. An operating head 66 iscarried on the 'valve' stem 60 on the opposite side of thesealingdiaphragm 64 therefrom to provide convenient means for moving thevalve member 54 to open position when desired. Such movement isaccomplished by a, pilot valve lever 68 which extends from the plunger30 to the operating head 66 and is suitably pivoted intermediate itsends in 'a bracket I0 carried on the casing I9.

Control valve mechanism As shown more clearly in Figs. '7 and 8, anannular valve seat member I2 is formed in the casing I0 in position tointersectthe passage of fuel from the inlet I2 tothe outlet I4 throughthe main fuel passage I6. An axial hollow boss I4 is formed within theannular valve seat 12 and provides a bearing for a valve stem 16 whichis reciprocable therein. A disc valve member I8 is mounted on the valvestem I6 for axial reciprocable movement therewith between open andclosed positions relative to the" valve seat 12. The valve member 78 isnormally biased toward the valve seat I2 by a coil spring 89 which isoperative between a closure cap 82 secured to the casing I0 and thevalve member I8.

The axial hollow boss 14 forms one wall of a chamber 84 in the casing I0which houses a snap-action means of conventional form comprising clickermechanism 86 and an annular thrust element88 for operating the valvemember 18 to open position against the bias of the coil spring 80. Thethrust element 89 carries a thrust button 90 which projects through asealing ring 92 forming an opposite wall for the chamber 84 and into arecess 9| formed in the casing I9. It will be observed that no fuel canflow from any of the various flow passages into the recess 9| due to thesealing arrangement.

Temperature regulation Thermally responsive means for operating thevalve member I8 through the clicker disc mechanism 8E-99 is carried byathermostat housing 94 which is secured to the exterior of the casing I0across the recess 9|. The housing 94 is provided with a threaded boss 96through which the usual rod-and-tube element 98, I00 projects into thestorage tank of 'a' water heater or the like (not shown). As iscustomary in such devices, the rod 98, has a relatively low coefficientof expansion while the tube I00 has a higher coe'fiicient of expansionand the differential under the influence of the heat of the water in thetank causes'the rod 98 to move outwardly of the easing I9. As shown moreclearly in Fig. 7, the rod element 98 projects into the recess 9| on oneside of the thrust button 99 and is axially movable in apathsubstantially parallel with that of the valve member 18.

Means are employed for transmitting motion between the rod element 98and the thrust button 99 and take the form of a first lever I92 which issupported intermediate its ends in the recess 9| on the rod 98. Afree'end I04 of the lever I92 is adapted for pivotal movement rela tiveto the thrust button 99 upon movement of the rod 98 relatively to thecasing I9 upon variations in the water temperature. Adjustable means areprovided for setting the temperature to be maintained by therod-and-tube element 98, I00 and take the form of an adjusting screw I99which extends through the casing I0 on an axis substantially parallelwith that of the valve member I8. One end of the adjusting screw I96projects exteriorly of the casing I0 and is provided with a pointer I08cooperable with a suitable scale IIO marked on the casing Ill. Theopposite end of the adjusting screw I96 projects into the recess 9| andis provided with an en-, larged head II2. A second lever H4 is mountedat one end for pivotal movement on the head H2 and is supported at itsopposite end by the first lever I02. Longitudinal alignment of leversI92 and I I4 is maintained by a pair of projections I I3 which dependfrom the lever I I4 for'engagement with opposite sides of the end I04 ofthe lever I 02. A raised portion H6 is provided on the second lever II4intermediate its ends-for operative engagement with the thrust button99in response to counterclockwise pivotal movement of the .first .leverI02 as will be hereinafter apparent.

Automatic pilot control The vapor-pressure type automatic pilot controlof this invention is adapted to render the rod-and-tube element 98,, Iineffective for overcoming the bias of the valve member I8- unless thepilot burner of the appliance is producing a flame. The automatic pilotcontrol comprises an actuating device including a bulb element I I8, acapillary tube I20 and a diaphragm unit I122 as is customary in suchdevices. The diaphragm unit I22 is connected to the capillary tube by acollar I23 which extends through a threaded bushing I24 carried by thecasing I0 for adjustment purposes. The, diaphragm unit I22 projects intoa chamber I26 formed in the casing I0 which communicates at one end withthe recess 9| but has no communication with any of the various flowpassages. V

The bulb element H 8 contains a quantity of mercury which becomesvaporized upon the bulb element being sufficiently heated and serves toactuate the diaphragm unit I 22 by expansion thereof. The expansion ofthe diaphragm unit I22 is transmitted to the first lever I02 through anoverride arrangement including a cage I28 secured by a riveted head I23or the like at one end to the lever I02 and having slidable connectionat the opposite end with a stud I30 projecting from the diaphragm unit I22. A loose collar I32 is mounted on the stud I30 within the cage I28and a coil spring I34 is operative between the collar I32 and theopposite end of the cage I28. When the rivet I29 bottoms on means to bedescribed the override arrangement provides a substantially unyieldingdevice should the force exerted by the diaphragm unit I22 be lessthanthe force of the spring I 34., However, if the force of the spring I34is' exceeded, then thecollar I32 is forced inwardlyof the cage I28 bytheexpansion of the diaphragm unit I22 and a yieldable mounting isprovided.

The rivet I29 engages with one endof a third lever I38, the opposite endof which extends into engagement with the operating head 60 of the pilotvalve 54. The third lever I38 is pivoted intermediate its ends on aplate. I 40 which is.

secured to the housing 94 within therecess 9| in the casing I0. Theplate I40 acts as a limiting stop for the override arrangement duringfree expansive movement of the diaphragm unit I22 by engaging the leverI38 and also serves as a fulcrum for this lever as willbe described. Itwill be apparent that the relationship. of'the dia phragm unit I22 withthe various levers is adjustable by means of the threaded bushing I24which abuts diaphragm unit I 22 for this purpose. It will also beapparent that when the rivet I29 engages the end of the lever I38 andmoves the end of the lever I02 into engagement With the plate I40, theend of the lever I02 thus moved will be accurately located in a specificrelation to the thrust button 90.

Operation The control device is placed in operativecondition by manualoperation when the knob 22 is rotated to the Pilot position and pushedin axially to engage the plunger 30 with the land portion 28. Theresulting movement of the plunger 30 causes the lever 68 to fulcrumabout the bracket in a counterclockwise direction as viewed in Fig. 4.The operating head 66, the pilot valve stem 60 and the pilot Valvemember 54 .pllot'valve member Hand the lever I38 is rotated in aclockwise direction about the edge of the stop plate I40 as a fulcrum.Fuelnow flows from the inlet I 2, angular port-20 m the main shut-offcock I8, passage 46, filter cartridge 42 ,hollow :boss 40, passage 50.,pilot valve seat 56, and through passage 58 to the connection SI for thepilot burner. It should be observed that in the ;'Pilot position of themain fuel cock I8 that the angular port 20 does not place the inlet I2in communication with the chamber I6; but merely ,in communication withthe pilot passage 46. v

The fuel flowing from the'pilot burner is then ignited manually Whilethe knob 22: remains depressed. The pilot name heats the bulb II8 whichis located adjacent to .the pilot burner and forces the diaphragm unitI22 .to expand. The

override arrangement comprising cage I28, collar I32 and coil spring I34is movedaxially toward the stop plate I40 carrying thelever I02 towardthe lever I38 until the latter is held securely against the stop plateI40 so that the free end of the lever I 38 hold thevalve member 54 inopen position. The knob 22 may then be released and further rotatedtoward the ON position. Should the diaphragm unit I22 expandloeyond thepoint at whiohthe' lever I33 seats against the stop plateI.40i:thenltheadditional movement is taken up by the: overridearrangement becoming a yieldablezdevice as previously described. p

It may be assumed that .the-rodaeIement-BB 'of the rod-and-tube thermaldevice 98-gI-00 is" in an advanced positionwithin "the rece'ss QI as theWater in the tank is stillicold and the tube element I00 is contracted.Consequently, with the lever I02 held against the 'stopplate I40 byoperation of the diaphragm I22, then the free end I04 will rotate in acounterclockwise direction about the rod element 98 as -afulcrurn.-'Such movement of the lever I02 will be transmitted to the lever I I4which will fulcrum about the-adjusting screw head H2 and rotate-inajclockwise direction. The thrust button is moved axially by the raisedportion I I 6 of thelever I, and causes the clicker mechanism8-6-f+880to snap over and actuate the valve member I8 too'pen position.The device is thus in normal running condition depending on thetemperatureset'by the pointer I08 on the scale IIO. l J v As the Waterin the tankincreases in temperature, the rod element '98 willberetractedaway from the casing I0 and, the force exerted by the leverM4 on the thrust button 90 will cease. Thus, the valve I8 will movetoward closed position relative to the valve seat 12 to shut-off flow offuel through the outlet I4 to the main burner. Such operation of thevalve member 18 between open and closed positionswill continue tomaintain the temperature set by the pointer I08.

Since the normal operating. position of the end of the lever I02 whichcooperates with the override unit is always the samedue to thepositioning feature of the stop'plate-I40, it will be apparent that thetemperature-at which the'thrust button is actuated by the lever II4 willdepend solely upon the location .of .the fulcrum of the lever II 4(adjusting screw'head H2). Thus the water temperature at which :thevalve member will be moved will depend solely upon thesetting of theadjusting screw I06.;: 3

Should the flame at the'pilot burner become extinguished then thebulbielement I..I8 wil1'be- "come'cooled allowing'the diaphragm unit I22to contract; The-axial movement ofthe override arrangement will retractthe end of the lever I 02 whichlis securedbythe rivet I29. Suchmovement' o'f-thelever I02 is in a clockwise direction about the rod'element 98 as a fulcrum and the free end I04 no longer exerts a forceupon the {lever I I4, Consequently, the valve spring 80 is free toexertits bias and the valve member 18 moves-to closed position to shut-01ffiow of fuel through the outlet- I4,

Simultaneously with operation of the lever I02 as described, the leverI38 is also caused tofollow the movement of the over-ride arrangement.Thus, as diaphragm I22 contracts, the pilot valve spring'59 is free toexert its bias for pivoting the lever I38 in a counterclockwisedirection about the edge of the stop plate I40. Hence, the pilot valvemember 54 moves to closed position to shut-off flow of fuel to the pilotoutlet fil. It is apparent that flowof fuel 'to both the main outlet I4'and the pilot outlet BI is completely out-01f upon cooling of the bulbelement H8 and no escape of fuel can occur. It is further apparent thatif a leak develops in theactuating element Il8 I22 that'a similarcomplete shut-off of 'fuel'will occur.

As previously indicated the recess SI and the chamber I26 in which thevarious levers and actuating means are'housed are both sealed off fromthe fuel passages. Consequently, these parts are not exposed to gumf-ormation'or cor rosion tending to, shorten the usual life orinterferewith.freeioperation.. 7

It will be understood that many changes may be made in the details ofconstruction and arrangementof parts without departing from the scope ofthis-invention as defined in the appended claims.

Weclaim: V U

1. A combined temperature and flame failure control comprising incombination, an axially reciprocablevalve means biased to a closedposition, a first thermally responsive device including a diaphragm unitpositioned for movement on an axis substantially parallel with saidvalve means, a second thermally responsive device in-, cluding amovablerod element, said diaphragm unit being movable toward said rod elementupon said first thermally responsive device being heated, a first levermounted for bodilymovement by said diaphragm unit and being operativelyengageable by said rod element intermediate said diaphragm unit and saidvalvemean's for pivotal movement relative to said valve means upon 'saidsecond thermally responsive d'evice being heated, adjustable means forsetting the temperature to be maintained by said second thermallyresponsivedevice, a Second lever mounted for pivotalfmovement on saidadjustable means and being operatively engageable with said first leverfor overcoming the bias of said valve means in response'to said pivotalmovement or said first lever, and means cooperable with said diaphragmunit forming a relaclosed position, manually operable means for openingone of said pair of valve means, a first thermally responsive deviceincluding a diaphragm unit positioned for movement on an axissubstantially parallel" with said pair of valve means, a secondthermally responsive device including a rod element, lever meansextending between said valve means and said diaphragm unit and beingoperatively engageable by said rod element intermediate said diaphragmuni-t and the other. said valve means for pivotal movement relative tosaid other valve means, means responsive tomovement of said lever andbeing effective in one thermal condition -of said first thermallyresponsive devicefor overcoming the bias of said other valve means butbeing ineifective in another said condition thereof, and means operableby said diaphragm unit for maintaining said one valve means in openposition while said first thermally responsive device remains in saidone thermal condition. I e

4. A combined temperature and automatic pilot control as claimedin claim3 wherein the free movement of said diaphragm unit is limited by astop,- and the last said means comprises a lever pivoted on said stop.

5. A combined temperature and automatic pilot co-ntrol'comprising incombination, a casing having an inlet and an outlet for fluid, arotatable valve member controlling a passage for fluid between saidinlet and outlet, a pilot valve means controlling a passage for fluidfrom said inlet under control of said rotatable valve member and beingbiased to a closed position, manually operable means for opening saidpilot 'valve means, an axially reciprocable valve means also controllingthe passage of fluid betweensaid inlet and outlet and being biased to aclosed position, said reciprocable valve means having an operatingportion projecting therefrom, said casing having a chamber into Whichsaid operating portion pr jec'ts and being sealed againstleakage offluid from said passage betweenjsaid' inlet and outlet, a firstthermally responsive device including a diaphragm unit positioned insaid chamber for movement on an axis substantially parallel with saidreciprocable valve means, a second thermally responsive device includinga movable rod element positioned in said chamber, a lever mounted onsaid diaphragm unit in said chamber and operatively engageable bysaidrod element intermediate said diaphragm unit and said reciprocablevalve means for pivotal movement relative to said reciprocable valvemeans, means respons ve to movement of said lever and being eifective none thermal condition of said first thermally responsive device foroperatively engaging said operating means and overcoming the bias ofsaid reciprocable valve means but being ineffective in another saidcondition thereof, and means operable by said diaphragm unit formaintaining said pilot valve means in open position while said firstthermally responsive device remains in said one thermal condition. 7

6. A combined temperature and automatic pilot control comprising incombination, a casing having an inlet and an outlet for fluid, arotatable valve member controlling a passage for fluid between saidinlet and outlet, a pilot valve means controlling a passage for fluidfrom said inlet under control of said rotatable valve member and beingbiased to a closed position, manually operable means for opening saidpilot valve means an axially reciprocable valve means also controllingthe passage of fluid between said inlet and outlet and being biased to aclosed position, a first thermally responsive device including adiaphragm unit positioned for movement on an'axis substantially parallelwith said reciprocable valve means, a second thermally responsive deviceincluding a movable rod element, said diaphragm unit being movabletoward said rod element upon said first thermally responsive devicebeing heated, a first lever mounted for bodily movement by saiddiaphragm unit and being operatively engageable by said rod elementintermediate said diaphragm unit and said reciprocable valve means, forpivotal movement relative to said reciprocable valve means upon saidsecond thermally responsive device being heated, adjustable means forsetting the temperature to be maintained by said second thermallyresponsive device, a second lever mounted for pivotal movement on saidadjustable means and being operatively engageable with said first leverfor overcoming the bias of said reciprocable valve means in response tosaid pivotal movement of said first lever, and a third lever mounted forpivotal movement by said diaphragm unit for maintaining said pilot valvemeans in open position while said first thermally responsive deviceremains heated.

'7. A combined temperature and automatic pilot control as claimed inclaim 6 wherein the free movement of said diaphragm unit is limited by astop upon which said third lever is pivoted, and a lost motionconnection between said diaphragm unit and said stop.

SAMUEL G. ESKIN. HAROLD W. RICE. ADELE M. ARKELYAN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,953,446 Strong Apr. 3, 19342,085,300 Dillman June 29, 1937 2,163,801 Newell June 27, 1939 2,303,128Koppel Nov. 24, 1942 2,337,164 McCarty Oct. 16, 1945

